Intuitively the metric can be understood by taking into account the possible edits that can transform \(U\)  into \(V\) : either we can align event \(u_\xi \)  and \(v_\theta \)  or we have to delete / create events in the spike trains. Both these edits appear in the RHS of (REF ). The cost of aligning two events is proportional to the time difference between the two events, e.g. \(\lambda | u_\xi -v_\theta |\)  controls the cost. Since the cost of creating and deleting events is chosen to be equal to 1, \(\delta \)  depends on the difference between the total number of events – given by \(\Xi +\Theta \)  – and twice the number of possible pairs – \(2|C|\) .
This Victor Purpura distance has been used to evaluate synchonization among neurons [1]}, [2]}.
Further details and a thorough mathematical description of the Victor Purpura distance can be found in the literature [3]}, [4]}, [5]}.
